Steerable tube

ABSTRACT

A steerable tube ( 100 ), comprising a hollow elongate tubular member ( 1 ) having a proximal end ( 2 ), distal end ( 3 ), a wall surface disposed between said proximal ( 2 ) and distal end ( 4 ), a bend-resistive zone ( 6 ) flanked by a proximal bendable zone ( 4 ) that forms a controller and a distal bendable zone ( 5 ) that forms an effector that moves responsive to movements of the controller, whereby the wall of the tubular member ( 1 ) in the bend-resistive zone ( 6 ) comprises a structure that is a plurality of longitudinal slits ( 7 ), forming a plurality of longitudinal strips ( 8, 8 ′), the wall of the tubular member ( 1 ) in the proximal bendable zone ( 4 ) and the distal bendable zone ( 5 ) comprises a structure that is a plurality of longitudinal wires ( 9, 9′, 10, 10′ ), at least one strip ( 8 ) is in connection with a wire ( 9 ) in the proximal bendable zone ( 4 ) and a wire ( 10 ) in the distal bendable zone ( 5 ), such that translation by said wire ( 9 ) in the controller is transmitted via the strip ( 8 ) to said wire ( 10 ) in the effector, a proximal annular region ( 11 ) of the tubular member ( 1 ), proximal to the proximal bendable zone ( 4 ) to which the proximal wires ( 9 ) are anchored, a distal annular region ( 12 ) of the tubular member ( 1 ) distal to the distal bendable zone ( 5 ) to which the distal wires ( 10 ) are anchored.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/787,538, filed Mar. 6, 2013, which is a divisional of U.S. patentapplication Ser. No. 12/866,003 filed Aug. 3, 2010, which is the U.S.National Phase under 35 U.S.C. § 371 of International ApplicationPCT/EP2009/051294, filed Feb. 5, 2009, which claims priority to EP08151060.4, filed Feb. 5, 2008. The contents of these priorityapplications are hereby incorporated herein in their entirety.

FIELD OF THE INVENTION

The invention relates to a steerable tube having enhanced control andsimplified construction, which can be used in high-precision or medicalapplications.

BACKGROUND OF THE INVENTION

The invention relates to an instrument for high-precision mechanicalapplications or for medical applications (e.g. surgery, endovascularprocedures, or for use as an endoscope) of a minimally invasive nature,comprising a hollow tubular member (1) having a proximal bendable zone(4) that forms a controller head, a distal bendable zone (5) that formsan effector—a steerable tip—and flexes responsive to movements of thecontroller, and, a bend-resistive zone (6) between the aforementionedzones (4, 5), that transmits movements of the controller to theeffector. The member is preferably formed from one or more substantiallysolid walled tubes. The high-precision instrument find applicationswhere exquisite, remote movements in confined spaces are needed, such asin medical applications, and in the inspection and repair of encaseddevices such as engines, pipelines, valves and other mechanical systems.

The notion an instrument having a steerable tip is known in the art. Forinstance, WO 03/037416 describes a mechanism that deflects portions of aflexible body such as a catheter in more than one direction in a singleplane, as well as in more than one plane by use of a pullwire. In orderto control the deflection of the distal end, many designs incorporateone or more steering cables. Mostly these cables are fed throughguide-sleeves located in the wall of the tube or in its lumen. Theseguide-sleeves that hold the steering cables in place are bulky and addto the cross-section of the wall.

For example, US-A-2006/0178556 (See FIGS. 1A and 1C), describes asteerable device having a ring of longitudinally extending cablesconnecting to the head, which cables are fixedly secured in the radialdirection. A disadvantage of this instrument is, however, that thecables are fed through guide-sleeves provided in the longitudinaldirection of the cables, which increase the diameter of the instrument.

A system to omit these sleeves has been described in WO 02/13682 (seeFIGS. 1B and 1D) which discloses a steerable device also of a ring ofcables comprising longitudinally extending cables connected to the head,which cables are fixedly secured in the radial direction. Instead of thecables being fed through guide-sleeves as in US-A-2006/0178556, they aredisposed side by side so filling the space where the guide sleeves wouldotherwise be. A disadvantage of this system is the high constructioncost for devices where lumen diameters need to be maximised for a givenouter diameter—i.e. the walls made thin which is a requirement for mostapplications. A rapid increase in the number of steering wires is seenwhen increasing the internal diameter while maintaining a thin wall, forexample, 25 steering cables of 0.2 mm for a lumen of 1 mm diameter.Furthermore, the alignment and correct pre-tensioning of a large numberof narrow diameter wires represents an enormous technical challenge.Further it is anticipated that the wires of narrowed diameter may slipcircumferentially within the sleeve, and tangle or wear.

It remains challenging to make an adequate affixation with the head andtip. Standard affixation techniques include soldering, clamping,crimping, use of small bolts, glue, knotting, cable U-turns throughrigid termination disk or laser-welding. Mostly these affixationtechniques result in bulky joints and some of them even weaken thewires.

Additionally, a compression spring is used in the art to pre-stress thetip, however, this reduces its torsion and bending stability, meaningthe tip can readily be deflected from a bent position by the applicationof an external force to the tip. Moreover, axial compression, forexample, by pulling the tool control wire during operation of thesurgical tool can induce straightening of the tip—a phenomenon known ascrosstalk which is to be avoided.

One particular application of a steerable tube is in the field ofneurosurgery. Neurosurgical endoscopic intraventricular procedures aretypically performed with a neurosurgical instrument known as theCaemaert endoscope. It is a long rigid shaft with an external diameterof ˜6 mm and four lumens. One lumen is for an optic element, one for aworking channel, and two for rinsing fluid. The endoscope is introducedthrough a burr hole in the skull; the shaft intrudes the brain tissue ata non-eloquent area before entering the fluid filled ventricles. Toreach the most central ventricle—known as the third ventricle—passagethrough an important ring-like structure, the foramen of Monroe, isnecessary. Damage to this structure causes amnesia. Access to the thirdventricle allows several surgical procedures to be performed such asperforating membranes or removing tumors. The latter is the mostchallenging procedure, requiring the sequential use of coagulation,grasping and aspiration. Using present technology, it is not possible tohave more than one steerable tube inside the endoscopic shaft,especially when one of the tubes is a steerable aspiration catheterwhich also requires a large lumen compatible with removal of particlesof tissue.

The present invention, therefore, address the problems of the art byproviding a steerable tube having a large diameter lumen whileminimizing the outer diameter, which is reliable and cost-effective tomanufacture.

SUMMARY OF THE INVENTION

One embodiment of the invention is a steerable tube (100), comprising ahollow elongate tubular member (1) having a proximal end (2), distal end(3), a wall surface disposed between said proximal (2) and distal end(3), the wall having a substantially uniform thickness, a bend-resistivezone (6) flanked by a proximal bendable zone (4) that forms a controllerand a distal bendable zone (5) that forms an effector, whereby

the wall of the tubular member (1) in the bend-resistive zone (6)comprises a structure that is a plurality of longitudinal slits (7),forming a plurality of longitudinal strips (8, 8′),

the wall of the tubular member (1) in the proximal bendable zone (4) andthe distal bendable zone (5) comprises a structure that is a pluralityof longitudinal wires (9, 9′, 10, 10′),

at least one strip (8) is in connection with a wire (9) in the proximalbendable zone (4) and a wire (10) in the distal bendable zone (5), suchthat translation by said wire (9) in the controller is transmitted viathe strip (8) to said wire (10) in the effector,

a proximal annular region (11) of the tubular member (1), proximal tothe proximal bendable zone (4) is circumferentially intact,

a distal annular region (12) of the tubular member (1) distal to thedistal bendable zone (5) is circumferentially intact.

Another embodiment of the invention is a steerable tube (100),comprising a hollow elongate tubular member (1) having a proximal end(2), distal end (3), a wall surface disposed between said proximal (2)and distal end (3), a bend-resistive zone (6) flanked by a proximalbendable zone (4) that forms a controller and a distal bendable zone (5)that forms an effector, whereby

the wall of the tubular member (1) in the bend-resistive zone (6)comprises a structure that is a plurality of longitudinal slits (7),forming a plurality of longitudinal strips (8, 8′),

the wall of the tubular member (1) in the proximal bendable zone (4) andthe distal bendable zone (5) comprises a structure that is a pluralityof longitudinal wires (9, 9′, 10, 10′),

at least one strip (8) is in connection with a wire (9) in the proximalbendable zone (4) and a wire (10) in the distal bendable zone (5), suchthat translation by said wire (9) in the controller is transmitted viathe strip (8) to said wire (10) in the effector,

a proximal annular region (11) of the tubular member (1), proximal tothe proximal bendable zone (4) to which the proximal wires (9) areanchored,

a distal annular region (12) of the tubular member (1) distal to thedistal bendable zone (5) to which the distal wires (10) are anchored.

Another embodiment of the invention is a steerable tube (100) asdescribed above, wherein one or more of the longitudinal strips (8, 8′)is aligned or inclined to a longitudinal (A-A′) axis of the hollowelongate tubular member (1).

Another embodiment of the invention is a steerable tube (100) asdescribed above, wherein one or more of the longitudinal strips (8, 8′)is at least partly linear.

Another embodiment of the invention is a steerable tube (100) asdescribed above, wherein one or more of the longitudinal strips (8, 8′)is provided with interconnections, non-radial slits or spiral cuts tohold the strips together.

Another embodiment of the invention is a steerable tube (100) asdescribed above, wherein the plurality of longitudinal wires (9, 9′, 10,10′) are separated by longitudinal apertures (13, 13′, 14, 14′) in theproximal bendable zone (4) and/or a distal bendable zone (5).

Another embodiment of the invention is a steerable tube (100) asdescribed above, wherein a wire (9, 9′, 10, 10′) in a bendable zone (4,5) is more narrow than a strip (8) in the bend-resistive zone (6).

Another embodiment of the invention is a steerable tube (100) asdescribed above, wherein the circumferential width of a wire (9, 9′, 10,10′) in the narrowest part, is between 50%, and 90% less than thecircumferential width of a strip (8) in the narrowest part.

Another embodiment of the invention is a steerable tube (100) asdescribed above, wherein the circumferential width of a wire (9, 9′, 10,10′) in the narrowest part, is between 0%, and 90% less than thecircumferential width of a strip (8) in the narrowest part.

Another embodiment of the invention is a steerable tube (100) asdescribed above, wherein one or more of the wires (9, 9′, 10, 10′) isaligned or inclined to a longitudinal (A-A′) axis of the hollow elongatetubular member (1).

Another embodiment of the invention is a steerable tube (100) asdescribed above, wherein one or more of the wires (9, 9′, 10, 10′) is atleast partly linear.

Another embodiment of the invention is a steerable tube (100) asdescribed above, wherein the proximal bendable zone (4) and/or distalbendable zone (5) is substantially formed from a material different tothat of the bend-resistive zone (6).

Another embodiment of the invention is a steerable tube (100) asdescribed above, further comprising an outer sheath (20), at leastpartly covering the outside surface of the hollow elongate tubularmember (1) while permitting translational movements of the strips (8,8′) and wires (9, 9′, 10, 10′) within.

Another embodiment of the invention is a steerable tube (100) asdescribed above, wherein the outer sheath (20), is flexible in theregion covering at least the bendable zones (4, 5).

Another embodiment of the invention is a steerable tube (100) asdescribed above, wherein the outer sheath (20), is less flexible in theregion covering the bend-resistive zone (6) compared with in the regioncovering at least the bendable zones (4, 5).

Another embodiment of the invention is a steerable tube (100) asdescribed above, further comprising an inner lining (50) that at leastpartly lines the lumen (15) of the hollow elongate tubular member (1)while permitting translational movements of the strips (8, 8′) and wires(9, 9′, 10, 10′) outside.

Another embodiment of the invention is a steerable tube (100) asdescribed above, whereby one or more of the apertures (13, 13′, 14, 14′)between the wires (9, 9′, 10, 10′) is provided with a spacer (16).

Another embodiment of the invention is a steerable tube (100) asdescribed above, further comprising a handgripper (70) at the proximalend (2), configured to control a set of forceps (80) at the distal end(3).

Another embodiment of the invention is a steerable tube (100) asdescribed above, further comprising an endoscopic camera or lens at thedistal end (3).

Another embodiment of the invention is a steerable tube (100) asdescribed above, further comprising a cutting tool (scissors, knife,drill, mill, grinder, knibbler) at the distal end (3).

Another embodiment of the invention is a steerable tube (100) asdescribed above, further comprising a sensor (temperature, moisture,light, gas, radioactivity) at the distal end (3).

Another embodiment of the invention is a steerable tube (100) asdescribed above, further comprising electrodes (stimulation, recording,coagulation) at the distal end (3).

Another embodiment of the invention is a steerable tube (100) asdescribed above, whereby the zones are formed from a substantially solidtube wall of the hollow tubular member during manufacture, and thebendable zones are formed by removing material from said substantiallysolid tube wall.

Another embodiment of the invention is a steerable tube (100) asdescribed above, whereby a wire (9) in the proximal bendable zone (4)and/or a wire (10) in the distal bendable zone (5) is disposed with oneor more cuts configured to increase flexibility of said wire

Another embodiment of the invention is a steerable tube (100) asdescribed above, whereby the proximal annular region (11) and/or distalannular region (12) are formed from one or more circumferentiallyinterlocking elements.

Another embodiment of the invention is a steerable tube (100) asdescribed above, whereby a wire (9) in the proximal bendable zone (4)and/or a wire (10) in the distal bendable zone (5) is connected to astrip by welding, gluing, soldering or by interlocking.

Another embodiment of the invention is a steerable tube (100) asdescribed above, whereby the thickness of a wire (9) in the proximalbendable zone (4) in its thinnest region and/or a wire (10) in thedistal bendable zone (5) is less than that of a connecting strip (8) inits thinnest region.

Another embodiment of the invention is a steerable tube (100) asdescribed above, whereby a wire (9) in the proximal bendable zone (4)and/or a wire (10) in the distal bendable zone (5) is made from a moreflexible material than use in a connecting strip (8).

Another embodiment of the invention is a steerable tube (100) asdescribed above, wherein the elongate tubular member (1) comprises aside port (40) formed from an aperture between two adjacent strips (8,8′).

Another embodiment of the invention is a steerable tube (100) asdescribed above, wherein the elongate tubular member (1) incorporates alimit stop mechanism (41) that limits the extent of relative slidablemovement between two strips (8, 8′).

Another embodiment of the invention is a steerable tube (100) asdescribed above, whereby elongate tubular member (1), and one of theouter sheath (20), or inner lining (50) are coaxially rotatableelements, further comprises a rotation limiting mechanism (44, 44′)formed from a radial protrusion (45 a, 45′a) present in any onecoaxially rotatable element, in longitudinal slidable connection with areciprocating slot (45 b, 45′b) in another coaxially rotatable elementof the steerable tube (100) configured to reduce or prevent revolutemovement by the elongate tubular member (1) relative to the outer sheath(20) or inner lining (50).

Another embodiment of the invention is a steerable tube (100) asdescribed above, further comprising an electromechanical actuatorconfigured to controllably move the proximal bendable zone (4) withinits range of movement, and optionally to rotate the steerable tube (100)around its longitudinal (A-A′) axis.

Another embodiment of the invention is a steerable tube (100) asdescribed above, further a braking mechanism, configured, to preventslidable movements by the strips (8, 8′) relative to the outer sheath(20) or inner lining (50).

Another embodiment of the invention is a steering guide (119-FIG. 17)comprising an elongated longitudinal member (122) having a proximal(126) and distal (128) end, the proximal end (126) disposed with a brace(123) for attachment to a part of a bodily arm, and the distal end (128)disposed with an endoport (160) configured for attachment to a medicalinstrument (120), said steering guide configured to place a proximal end(126) of the instrument in the vicinity of the hand (138) of said arm,and for pivotal movement of the instrument (120) actuated by movementsaid part of the arm.

Another embodiment of the invention is a lockable articulated arm(170-FIG. 18) comprising a plurality of tandemly arranged, rigid links(172, 174, 176, 178) connected by lockable joints (180, 182, 184) havingat one end a base link (172) configured for rigid attachment to anoperating table (171), and at the other end, an effector link (178)connected to a lockable ball and socket joint (152), the ball and socketjoint configured for coupling to an endoport device (160), through whicha medical instrument (120) is disposed, which lockable ball joint (152)is further configured to pivot the endoport device (160) relative to theeffector link (178).

Another embodiment of the invention is a rotation limiting mechanism fora steerable tube comprising a plurality of cables arranged in acylinder, circumferentially flanked by an inner and outer tubularsupport whereby the cylindrically arranged cables, and one of the innerand outer tubular supports are coaxially rotatable elements, whichrotation limiting mechanism is formed from a radial protrusion presentin any one coaxially rotatable element, in longitudinal slidableconnection with a reciprocating slot in another coaxially rotatableelement of the steerable tube configured to reduce or prevent coaxiallyrotation by the cylindrically arranged cables relative to the inner orouter tubular support.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1A and 1B show cut away sections devices in the art comprising aplurality of cables fed through guide sleeves (FIG. 1A) or disposed sideby side (FIG. 1B).

FIGS. 1C and 1D show transverse sections across the devices of the artshown in FIGS. 1A and 1B respectively, together with indications ofouter (OD) and inner (ID) tube diameters.

FIG. 2A shows cut away section device of the present inventioncomprising an elongate tubular member 1, disposed with both optionalouter sheath 20 and inner tube 50. The outer sheath and inner tube,explained below as not being essential, are shown to facilitatecomparison with the prior art.

FIG. 2B shows axial view section device of the present invention,together with indications of outer (OD) and inner (ID) tube diameters. Afavorable comparison with the dimensions of devices known in the art isapparent.

FIG. 3A depicts a perspective view of a steerable tube of the presentinvention in a non-bent state.

FIG. 3B depicts a perspective view of a steerable tube of the presentinvention whereby the proximal and distal bendable zones are flexed.

FIG. 4A illustrates the dimensions of a steerable tube of the presentinvention, and FIGS. 4B to 4D illustrates the dimensions of thetransverse cross sections.

FIG. 5 depicts a perspective view of the proximal bendable zone disposedwith a spacer in the apertures.

FIG. 6A to 6C depicts alternative configurations for a spacing means tostabilize the wires. In FIG. 6A, alternate wires are bent in anundulating form, in FIG. 6B, the wires are disposed with teeth, in FIG.6C the wires is disposed with hollow rings.

FIG. 7 depicts a perspective view of an outer sheath.

FIGS. 8A to 8C depicts perspective views where the strips are providedwith additional circumferential cuts (FIG. 8A), and examples of radialand non-radial slits (FIG. 8B) or an interconnection (FIG. 8C).

FIG. 9A depicts a side port created by cutting of apertures between twoadjacent strips to allow lateral exit of, for example, wires, electricalcables or aspiration ducts.

FIG. 9B depicts a limit stop mechanism that controls the extent ofslidable movement by two strips, which limits stop is formed from atooth fixed to one strip in slidable connection with a reciprocatingnotch in an adjacent strip that limits, for instance, the angle ofmotion of the instrument.

FIG. 10A. depicts an example of a rotation stop formed from a radialprotrusion (a keel) fixed to the inner tube, in slidable connection witha reciprocating slot formed between two strips of the elongate tubularmember, which rotation stop decreases the torsion of steerable tubearound the central axis relative to the inner tube.

FIG. 10B depicts a further example of a rotation stop formed from aradial protrusion (keel) fixed to the inner tube, in slidable connectionwith a reciprocating slot formed from a remove strip of the elongatetubular member, which rotation stop decreases torsion of strips aroundthe central axis relative to the inner tube.

FIGS. 11A and 11B depict the keel of FIGS. 10A and 10B in a detailedview.

FIG. 12 illustrates a perspective view of the distal bendable zone,where four strips are provided with piezomotors.

FIG. 13A illustrates a perspective view of coaxial steering tubes

FIG. 13B depicts a sequence of tandemly arranged steerable tubes(motorized), forming a snake-like articulated tube having severaldegrees of freedom of movement.

FIGS. 14A and 14B illustrate a steerable tube from the assembly ofseveral parts to form an intact annular region for anchoring the wires.

FIGS. 15A to 15D provide perspectives view of a steerable tube adaptedwith a gripper (FIGS. 15A and B) and forceps (FIGS. 15C and D).

FIG. 16A illustrate a perspective view of the proximal bendable zone,where the strips are joined to rod-shaped wires, which wires are madefrom a different material (e.g. Nitinol) from the strips (e.g. made fromstainless steel).

FIG. 16B illustrate a perspective view of the proximal bendable zone,where the strips are joined to the wires by a joint, which wires aremade from a different material from the strips.

FIG. 17 shows a schematic view of a steering guide for supporting andpivotally moving an invasive medical instrument having a longitudinalaxis, within a bodily cavity.

FIG. 18 shows a schematic view of a lockable articulated arm of theinvention.

FIG. 19 shows a cross-sectional view of the ball and socket joint andendoport that forms part of the lockable articulated arm.

DETAILED DESCRIPTION OF THE INVENTION

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as is commonly understood by one of skill in theart. All publications referenced herein are incorporated by referencethereto. All United States patents and patent applications referencedherein are incorporated by reference herein in their entirety includingthe drawings.

The articles “a” and “an” are used herein to refer to one or to morethan one, i.e. to at least one of the grammatical object of the article.By way of example, “a linkage” means one linkage or more than onelinkage.

The recitation of numerical ranges by endpoints includes all integernumbers and, where appropriate, fractions subsumed within that range(e.g. 1 to 5 can include 1, 2, 3, 4 when referring to, for example, anumber of object, and can also include 1.5, 2, 2.75 and 3.80, whenreferring to, for example, measurements). The recitation of end pointsalso includes the end point values themselves (e.g. from 1.0 to 5.0includes both 1.0 and 5.0)

The terms “distal” and “proximal” are used through the specification,and are terms generally understood in the field to mean towards(proximal) or away (distal) from the surgeon's side of the apparatus.Thus, “proximal” means towards the surgeon's side and, therefore, awayfrom the patient's side. Conversely, “distal” means towards thepatient's side and, therefore, away from the surgeon's side.

Reference is made in the description below to the drawings whichexemplify particular embodiments of the invention; they are not at allintended to be limiting. It will be understood that the skilled personmay adapt the device and substitute components and features according tothe common practices of the skilled artisan.

The present invention relates to a steerable tube with thin-walls andhaving ends that can move in omni-directional manner and aremechanically coupled. With reference to FIGS. 3A and B an embodiment ofthe present invention concerns steerable tube 100, comprising a hollowelongate tubular member 1 having a proximal end 2, a distal end 3, awall surface disposed between said proximal 2 and distal end 3, abend-resistive zone 6 flanked by a proximal bendable zone 4 that forms acontroller and a distal bendable zone 5 that forms an effector, whereby:

the wall of the tubular member 1 in a bend-resistive zone 6 comprises astructure that is a plurality of longitudinal slits 7, forming aplurality of longitudinal strips 8, 8′,

the wall of the tubular member 1 in a proximal bendable zone 4 and adistal bendable zone 5 comprises a structure that is a plurality oflongitudinal wires 9, 9′, 10, 10′,

at least one strip 8 is in connection with a wire 9 in the proximalbendable zone 4 and a wire 10 in the distal bendable zone 5, such thattranslation by said wire 9 in the controller is transmitted via thestrip 8 to said wire 10 in the effector,

a proximal annular region 11 of the tubular member 1, proximal to theproximal bendable zone 4,

a distal annular region 12 of the tubular member 11 distal to the distalbendable zone 5.

Another embodiment, of the present invention is a hollow elongatetubular member 1 having a proximal end 2 and distal end 3, comprising:

a wall surface disposed between said proximal 2 and distal end 3,

a proximal bendable zone 4 that forms a controller,

a distal bendable zone 5 that forms an effector and flexes responsive tomovements of the controller, and,

a bend-resistive zone 6 between the aforementioned zones 4, 5 thattransmits movements of the controller to the effector, whereby:

the wall of the tubular member in the bend-resistive zone 6 comprises astructure that is a plurality of longitudinal slits 7, flanking aplurality of longitudinal strips 8, 8′,

the wall of the tubular member in proximal bendable zone 4 comprises astructure that is a plurality of longitudinal proximal wires 9, 9′,

the wall of the tubular member in distal bendable zone 5 comprises astructure that is a plurality of longitudinal distal wires 10, 10′,

at least one strip 8 is in connection with a wire 9 in the proximalbendable zone 4 and a wire 10 in the distal bendable zone 5, such thattranslation by said wire 9 in the controller is transmitted via thestrip 8 to said wire 10 in the effector,

a proximal annular region 11 of the tubular member 1, is proximal to theproximal bendable zone 4, and

a distal annular region 12 of the tubular member 11 is distal to thedistal bendable zone 5.

The steering technology is formed in the wall of the tubular member 1itself, thereby reducing significantly the wall thickness, and obviatingthe requirement of cables and associated technical difficulties withconnecting, aligning and pre-tensioning cables cables. The steerabletube 100 is typically formed from a single, substantially solid-walledhollow elongate tubular member 1 which may be cut according to theinvention, preferably using an accurate cutting system. Affixationtechniques are not essential, and thus bulky joints typically associatedwith conventional tubes may be avoided, and do not conflict with anarrow profile. The invention thus provides a streamlined continuationof steering strips to the ends of the tube, whereby the risk of breakageis significantly reduced. Sterilization is facilitated since the partsare dismountable.

Alternatively the tubular member is formed by assembling one or moreseparately formed jig-sawed pieces.

Bendable Zones

A bendable zone 4, 5 is a region in which the hollow elongate tubularmember 1 is able to flex i.e. diverge from a longitudinal axis (A-A′) ofthe bend-resistive zone 6. Preferably, the tubular member 1 is able tobend in any direction providing left, right, forward, backwardsmovements, and movements in between to the effector. The construction ofthe device may alternatively allow a restricted movement, for example,when a plurality of wires 9, 9′, 10, 10′ is connected to the same strip8 providing, for instance, only a left and right movement by thebendable zone 4, 5.

According to one aspect of the invention, the wall of the tubular memberin proximal bendable zone 4 comprises a structure that is a plurality oflongitudinal proximal wires 9, 9′ separated by longitudinal apertures13, 13′. In this instance, flexibility in the bendable zones 4, 5 isachieved in principal by the longitudinal apertures 13, 13′, 14, 14′ inthe wall of the elongate tubular member 1 which are shaped to provide aplurality of narrow wires 9, 9′, 10, 10′. The apertures and hence wiresare preferably evenly arranged around the circumference of the elongatetubular member, thereby forming a tubular wall that can bend withoutkinking. The number of wires 9, 9′, 10, 10′ is preferably 1, 2, 3, 4, 5,6, 7, 8 or more. The number of apertures 13, 13′, 14, 14′ is preferably2, 3, 4, 5, 6, 7, 8 or more.

The skilled person will appreciate that the bendable zones 4, 5 maystill have the requisite bending properties even when longitudinalapertures 13, 13′ are absent. In such case, a wire 9, 9′, 10, 10′ willhave the same circumferential width as a strip 8 and may be an extensionof a strip 8. Typically an outer sheath 20 will contribute to thedifferential flexibility in the bendable zones 4, 5 and bend resistivezone 6 as explained elsewhere herein. The wires 9, 9′, 10, 10′ arepreferably evenly arranged around the circumference of the elongatetubular member, thereby forming a tubular wall. The number of wires 9,9′, 10, 10′ is preferably 1, 2, 3, 4, 5, 6, 7, 8 or more.

A wire 9, 9′, 10, 10′ in a bendable zone 4, 5 may be more narrow than astrip 8 in the bend-resistive zone 6, and consequently is able to adoptmore flexibility which contributes to the bending property of the zones.Alternatively, a wire 9, 9′, 10, 10′ in a bendable zone 4, 5 may be thesame width as a strip 8 in the bend-resistive zone 6 as explainedherein. According to one aspect of the invention, the circumferentialwidth of a wire 9, 9′, 10, 10′ (WPW or WDW) in the narrowest part, is0%, 1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 90% less than the circumferential width ofa strip 8, (WS) in the narrowest part, or a value in the range betweenany two of the aforementioned values. Preferably the value of WPW or WDWis between 50% and 80%, or between 0% and 80% less than the value of WS,though in practice the precise percentage will depend on the finaldiameter of the elongate tubular member and material used.

According to one aspect of the invention, the steerable tube has one ormore spacers configured to maintain distance between the wires. If awire 9, 9′, 10, 10′ is narrowed extensively, for example, when usingonly three strips 8, the use of a spacer 16 (see FIG. 5) in one or moreof the apertures 13, 13′, 14, 14′ between the narrow wires 9, 9′, 10,10′ may provide smoother movements by reducing buckling of the wires,though it is not essential. It will be appreciated that a spacer may becurved to match the cylindrical curvature of the elongate tubular member1.

The spacer 16 may be attached to the annular region 11, 12. Parts of thewall left behind during the laser-cutting can create these fixedspacers.

Alternatively, spacing between the wires may be maintained by employingone or more spacers on a wire 9, in fixed attachment thereto, configuredfor slidable contact with an adjacent wire 9′ thereby maintaining itsdistance therefrom.

According to one aspect of the invention, the aforementioned wire-boundspacer is formed by one or more bends in the wire 9. The wire so bent17, 17′ may have a undulating shape as shown, for example in FIG. 6A.The undulations, having a concave (upper) and convex (lower) part, arein slidable contact with straight (non-bent) wires 9, 9′ adjacent onboth sides. It is within the scope of the invention that the bent wirehas a concave or convex undulation (not shown), and the undulation is inslidable contact with a straight region of an adjacent wire on one side.

The number of undulations per wire, where present, may be 1, 2, 3, 4, 5,6, 7, 8, 9, 10 or more, depending on the size of the undulation and thelength of the wire. For example, the bent wire 17, 17′ depicted in FIG.6A is disposed with 5 undulations.

Alternatively or in addition, an aforementioned wire-bound spacer isformed from a tooth-shaped protrusion in fixed attachment to a wire,configured to slidably contact an adjacent wire. A tooth-shaped spacer18, 18″, may be attached in either a concave or convex relation to thelongitudinal length of the wire, and is in slidable contact a straightregion of an adjacent wire on one side as shown, for example, in FIG.6B. Alternatively, two or more tooth-shaped spacers may be attached onein a concave and another in a convex relation to the longitudinal lengthof the wire, and is in slidable contact a straight region of adjacentwires on both sides (not shown). Said adjacent wires may be straight, ormay be disposed with one or more teeth. The number of tooth-shaped perwire, where present, may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more,depending on the size of the undulation and the length of the wire. Forexample, the wire 9, 9′ depicted in FIG. 6B is disposed with 2undulations.

Alternatively or in addition, an aforementioned wire-bound spacer may beformed from the structure arising when the above-mentioned concave andconvex undulations are superimposed at the same position on the wire,i.e. a ring-shaped spacer is formed that is in slidable contact with astraight region of adjacent wires 9, 9′ on both sides. Said adjacentwires may be straight, or may be disposed with one or more ring-shapedspacers. Said ring shaped spacers 19, 19′ may be formed from a hollowring as depicted in FIG. 6C, or from a solid ring (not shown). The ringmay be circular or oval. The number of rings per wire, where present,may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more, depending on the size ofthe ring and the length of the wire. For example, the wire 9, 9′depicted in FIG. 6C is disposed with 1 undulation.

It will be appreciated from the above that the invention includes anyother cutting patterns to maintain spacing between the wires within itsscope.

It is an option that one or more of the wires 9, 9′, 10, 10′ in thebendable zones 4, 5 is thinned i.e. reduced in material thickness (TP orTD) to provide increased flexibility. Thinning may be achieved bychemical etching or other techniques known in the art. It is an optionthat one or more of the wires 9, 9′, 10, 10′ in the bendable zones 4, 5is rounded to remove sharp corners. Rounding may be achieved byelectropolishing or other techniques known in the art.

The wires 9, 9′, 10, 10′ that provide flexibility need not be linear andaligned with the longitudinal (A-A′) axis in an unflexed state as shownin the FIG. 4A, for example. One or more of the wires 9, 9′, 10, 10′ maybe aligned with or inclined to the longitudinal (A-A′) axis of thehollow elongate tubular member 1. One or more of the wires 9, 9′, 10,10′ may be at least partly linear, though other patterns are envisaged,for example, wires that are undulating 17 (FIG. 6A), or curved shaped orany suitable pattern as seen, for instance, in stent production are allwithin the scope of the invention. As mentioned earlier, one or morewires may be disposed with tooth-shaped spacers 18 (FIG. 6B), ordisposed with ring-shaped spacers 19 (FIG. 6C).

According to one aspect of the invention, a wire 9 is a solid nitinolrod 95, 95′ inserted or laser welded in a small burr hole in the strip 8and annular region 11 (FIG. 16A).

According to another aspect of the invention, a wire 9 is made from adifferent material to the adjoining strip 8, and is attached to thestrip by joint 90 (FIG. 16B). The joint 90 is preferably a dove-tailjoint, or the like.

Controller

When the controller (proximal bendable zone 4) is flexed, its movementsare transmitted via the bend-resistive zone 6 to the effector (distalbendable zone 5) which flexes responsive to movements of the controller.The controller may be manually manipulated or it can be coupled tomechanical movement means (e.g. electromechanical). In the latter case,the movements of the controller may be servomechanically actuated, forexample, by use of a telesurgical system. Electromechanical movement mayalso alternatively or additionally be realised by the use of linearmotors that operate on the strips 8 of the tubular member 1 as describedelsewhere herein.

Increased bending-couple or leverage in the proximal bendable zone 4(controller) can be achieved by a progressive increase of the tubularmember 1 diameter towards the proximal end 2 in comparison to the restof the elongate tubular member. According to one aspect of theinvention, the diameter of the tube in the proximal bendable zone 4 is5%, 10%, 15%, 20%, 25%, 30%, 50%, 100%, 200%, 300%, 400%, 500%, 600%,700%, 800%, 900%, 1000%, 2000% or more, greater than the diameter of thetube in the remainder of the tube when comparing the maximum diameter ofthe proximal bendable zone 4 with the minimum diameter of the remainderof the tube, or a value in the range between any two of theaforementioned values.

Alternatively the proximal end could be fixed to a gimbal-plate orgimbal-ball. This increased bending-couple might be of interested forthe mostly long endovascular catheters in which more force-lost is seendue to torturous path of the tube in the vascular structures.

As mentioned elsewhere, the proximal bendable zone 4 (controller) may becoupled to a mechanical movement means, particularly to anelectromechanical means. One embodiment of the invention, is anelectromechanical controller for a steerable tube 100 of the inventioncomprising a holder configured for dismountably attaching a steerabletube of the invention, and an electromechanical actuator configured tocontrollably move the proximal bendable zone 4 (controller) within itsrange of movement, and optionally to rotate the steerable tube aroundits central axis. The holder preferably attaches in the region of thebend-resistive zone 6. The attachment is dismountable, meaning thatsteerable tubes can be interchanged with the same controller; this hasthe advantage that a steerable tube may be removed for sterilization orreplaced where necessary without need for changing the electromechanicalcontroller. The electromechanical actuator may comprise two or moreservo motors, arranged for two or three axis control around a pivotalpoint of the proximal bendable zone 4. The skilled person will be ableto implement suitable working configuration of the electromechanicalcontroller based on the guidance herein.

Effector

The effector (distal bendable zone 5) moves responsive to movements ofthe controller, typically in mirrored manner. For example, a forwardmovement by the controller will result in a backward movement by theeffector and vice versa.

The effector of the invention provides an excellent steering stabilityas a result of several factors. A large bending moment is availablesince the wires terminate at a far lateral offset relative to the tubecenterline. Further, both pulling and pushing are transmitted to theeffector, which forces cooperate to provide both a large net mechanicalforce and exquisite control. The effector has a high bending stiffnessto limit undesirable deflections such as S-shape bending and has a hightorsional stiffness. The effector can withstand severe lateral loads andallows axial rotation (transmission of torque) even in a bent position.This is particularly of importance for example, if it is required tobring together the jaws of a scissor perpendicular to a blood vessel.

The elongate tubular member 1 of the invention is hollow, thus it mayact as a lumen providing a passage from the proximal 2 to the distal 3tip of the elongate tubular member. The effector, therefore, is providedwith the lumen which can receive operating wires or fluids when thelumen is lined with a water impermeable substance.

Furthermore, the effector may be adapted to support one or moreadditional instruments for remote operation such as clamps, graspers,scissors, staplers, aspiration catheter, laser fibers and needleholders. The adaptation of the effector will be readily understood bythe skilled artisan, and is discussed further below.

Bend Resistive Zone

The bend-resistive zone 6 connects the proximal bendable zone 4 with thedistal bendable zone 5 and transmits movements of the controller to theeffector. The wall of the tubular member in the bend-resistive zone 6comprises a structure that is a plurality of longitudinal slits 7, thatflank a plurality of longitudinal strips 8, 8′. The slits cut across thebend-resistive zone 6 in the longitudinal (A-A′) direction allowing eachstrip to slide independently of the adjacent strip. In transmittingforces, the strips exhibit negligible compliance and thus efficient useis made of almost the complete wall structure. It will be apparent thatwhen the strips are aligned adjacently to form the hollow elongatetubular member 1, the flexibility of the bend-resistive zone 6 isreduced. The bend-resistive zone 6 is considerably less flexible thanthe bendable zones 4, 5. The flexibility may be attributable, forexample, to the presence of no or few apertures which would otherwiseprovide flexibility. Alternatively, the inner lining or outer sheath inthe bend resistive zone may be less flexible than in the bendable zone.The longitudinal slits 7 and hence longitudinal strips 8, 8′ arepreferably evenly arranged around the circumference of the elongatetubular member. The number of longitudinal strips 8, 8′ is preferably 2,3, 4, 5, 6, 7, 8 or more. The number of longitudinal slits 7 ispreferably 2, 3, 4, 5, 6, 7, 8 or more.

The degree of bendability in the bend-resistive zone 6 while being lessthan that in the bendable zones 4, 5 will depend on the number oflongitudinal strips 8, 8′ or slits 7, the material used to form theelongate tubular member 1 and its thickness.

As mentioned already, at least one strip 8 is in mechanical connectionwith a wire 9 in the proximal bendable zone 4 and a wire 10 in thedistal bendable zone 5, such that translation by said wire 9 in thecontroller is transmitted via the strip 8 to said wire 10 in theeffector. The connection is generally rigid. The number of wiresconnected to a single strip is typically two—one proximal wire 9, 9′ andone distal wire 10, 10′—however, it is not necessarily limited to thisnumber. It is envisaged that more than two wires can be connect to asingle strip 8 in order to provide, for example, a restricted movementwhich can be desirable in applications where the full range of motionmight otherwise lead to damage to the object being inspected or operatedon.

As mentioned above, the circumferential width of a wire 9, 9′, 10, 10′(WPW or WDW) of a bendable zone, in the narrowest part, is 0%, 1%, 2%,3%, 4%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%,70%, 75%, 80%, 90% less than the circumferential width of a strip 8,(WS), of the bend-resistive zone 6, in the narrowest part, or a value inthe range between any two of the aforementioned values. Preferably thevalue of WPW or WDW is between 50 and 80%, or between 0 and 80% lessthan the value of WS, though in practice the precise percentage willdepend on the final diameter of the elongate tubular member and materialused.

The longitudinal slits 7 and hence longitudinal strips 8, 8′ need not belinear and aligned with the longitudinal (A-A′) axis as shown in, forexample, FIG. 4. One or more of the longitudinal strips 8, 8′ may bealigned or inclined to a longitudinal (A-A′) axis of the hollow elongatetubular member 1. One or more of the longitudinal strips 8, 8′ may be atleast partly linear, though other patterns are envisaged, for example,spiral strips, or any suitable pattern as seen, for instance, in stentproduction.

According to one aspect of the invention, the bend resistive zonecomprises a braking mechanism, configured, when activated to preventslidable movements by the strips 8, 8′. When the brake is applied, theposition of the distal bendable zone 5 is fixed; i.e. it becomesresistive to force applied thereto. The brake may take any form, forexample, a compressible annular ring having an inner diameter thatvaries according to the degree of compression. The inner circumferenceof the ring applies pressure to the strips 8, 8′ of the elongate tubularmember 1 when the ring is compressed along its central axis.

According to one aspect of the invention, the elongate tubular member 1comprises a side port 40 created by cutting an aperture between twoadjacent strips 8, 8′ as shown, for example, in FIG. 9A. The aperture isdimensioned to maintain integrity of the strip in the longitudinaldirection. The width of the region of a strip that form said aperturemay be less than the width, WS (FIG. 4C), of a strip. The side port 40allows side access to a hollow of the steerable tube 100 or inner lining50. The side port 40 may allow exit of wires, electrical cables oraspiration ducts from a hollow of the elongate tubular member 1 or innerlining 50. Alternatively or in addition, side port 40 may be in fluidconnection with the distal 3 tip of the steerable tube 100, allowing theintroduction of liquids (e.g. medicaments, washing solutions, contrastagents) and/or aspiration in the vicinity of the distal 3 tip. Theskilled artisan will appreciate that any inner lining 50 or outer sheath20 will be disposed with a corresponding aperture, aligned with theaperture formed in the elongate tubular member 1.

According to one aspect of the invention, the elongate tubular member 1incorporates a limit stop mechanism 41 that controls the extent ofrelative slidable movement between two strips 8, 8′. In a preferredembodiment, depicted in FIG. 9B, the limit stop 41 is formed from atooth 42 a fixed to the edge of one strip 8 in slidable connection witha reciprocating notch or crenellation 42 b in an edge of an adjacentstrip 8′. Movement of the tooth 42 a within the notch 42 b is limitedwhen the tooth 42 a contacts the distal or proximal notch 42 b edges atthe extreme ranges of movement. The limit stop mechanism 41 ispreferably located within the bend resistive zone 6. The effect of thelimit stop is to restrict, for instance, the extent to which theinstrument flexes i.e. the maximum angle of flexure.

According to one aspect of the invention, the steerable tube 100 furthercomprises a rotation limiting mechanism 44, 44′ (FIGS. 10A and B) formedfrom a radial protrusion (known as a keel herein) 45 a, 45′a present inone coaxially rotatable element (e.g. the elongate tubular member 1) inlongitudinal slidable connection with a reciprocating slot 45 b, 45′b inanother coaxially rotatable element (e.g outer sheath 20 or inner lining50) of the steerable tube 100 configured to reduce or preventunwarranted revolute movement by the elongate tubular member 1 relativeto the outer sheath 20 or inner lining 50. While in the above examplethe keel 45 a, 45′a is present in the elongate tubular member 1 and theslot is present in the outer sheath 20 or inner lining 50, it is withinthe scope of the invention that a slot may be present on the elongatetubular member 1 and the keel present on the outer sheath 20 or innerlining 50. The rotation limiting mechanism 44, 44′ is preferably locatedwithin the bend resistive zone 6. The rotation limiting mechanism 44,44′ is of importance when lateral forces are applied to the tip of theinstrument in a bent position, which would otherwise cause the tip tomove and lose its placement.

The slot 45 b, 45′b may be any shape, depending on the desired movementat the distal end 3, though it should be narrow and engage with the keel45 a, 45′a sufficiently prevent free rotation of the distal bendablezone 5 upon the application of a torque thereto. Preferably, the slot 45b, 45′b is straight and parallel with the longitudinal axis (A-A′) ofthe bend-resistive zone. According to one aspect of the invention a slotis formed along at least part of the length of a strip 8, 8′. Accordingto another aspect of the invention a slot is formed along at least partof the length between of two adjacent strips 8, 8′. According to anotheraspect of the invention a slot is formed form a strip of the elongatetubular member 1 disconnected from the wires or annular regions as shownin FIG. 10B.

Should a rotation movement be desired at the distal bendable zone 5, theslot may be spiral. The spiral may permit an anti-clockwise or clockwiserotation simultaneous with flexure of the distal bendable zone 5. Thekeel may be, but not necessarily, considerably shorter than the lengthof a strip. FIGS. 10A and 10B depicts a steerable tube 100 disposed witha rotation limiter 44, 44′ in which the keel 45 a, 45′a is disposed onthe inner lining 50 and the slot 45 b, 45′b is disposed on the elongatetubular member 1. FIGS. 11A and 11B show in detail the keel 45 a of theinner lining 50 disposed within the elongate tubular member 1 depictedin FIGS. 10A and 10B respectively. Preferably there are 1, 2, 3, 4, 5,6, 7, 8, 9 or 10 or more keel and slot pairs along the same linear path,depending on the length of the keel and of the steerable tube 1.Preferably there is at least one keel every 20, 30, 45, 60, 72, 90, 120,or 180 degrees.

It is within the scope of the invention that the above-mentionedrotation limiter 44, 44′ is applied to any device, operating alongsimilar principles, whereby forces are transmitted by a transmissionmeans (e.g. strips, rods or cables) covered with anindependently-rotatable inner or outer lining. For example, one or morecables of FIG. 1D may be disposed with a keel that is in longitudinalslidable connection with a reciprocating slot in an outer sheath orinner lining of the steerable tube, which arrangement is configured toreduce or prevent unwarranted revolute movement by the cylinder ofcables. One embodiment of the invention is rotation limiting mechanismfor a steerable tube comprising a plurality of cables arranged in ahollow cylinder, circumferentially flanked by an inner and/or outertubular support whereby the cylindrically arranged cables, and one ofthe inner and outer tubular supports are coaxially rotatable elements,which rotation limiting mechanism is formed from a radial protrusionpresent in any one coaxially rotatable element, in longitudinal slidableconnection with a reciprocating slot in another coaxially rotatableelement of the steerable tube configured to reduce or prevent co-axialrotation by the cylindrically arranged cables relative to the inner orouter tubular support.

According to one aspect of the invention, the controller may operated bythe use of linear motors such as piezomotors (e.g. Piezo LEGS®). Suchpiezomotors 60 may be arranged radially around the strips (inside oroutside, parallel or sequential) of the tubular member 1 (FIG. 8).Piezomotors 60 may be arranged around the inside or outside of thetubular member 1 (FIG. 8). There may be one or more (e.g. 1, 2, 3, 4, 5,6, 7, 8, 9, 10 or more) piezomotors 60 per strip 8. The movement part ofa piezomotor 60 is in mechanical contact with a strip 8, while a frameof the piezomotor 60 may be attached to a static element on thesteerable tube, such as an outer sheath 20 (not shown).

According to one aspect of the invention, the strips may be actuatedusing Flexinol®. Flexinol® actuators contract, in a similar manner tomuscles, by a shortening or elongation of approximately 4-5%; thus theycontract when they are “on” and relax when they are “off”. Movement ofthe strips may be achieved by arranging insulating strips placed betweenthe actuating strips 8 of the hollow member 1. Advantageously, the useof linear motors allow a plurality of motorized steerable tubes to beconnected, end to end, that offers a snake like tube (FIG. 13B) having awide range of motion at the effector end. It is not essential that theproximal bendable zone 4 is present in such a configuration. When thesteerable tubes 100 are joined by motorized revolute joints, the rangeof motion is further enhanced. One embodiment of the invention is acomposite steerable tube formed from two or more (e.g. 2, 3, 4, 5, 6, 7,8, 10 or more) motorised steerable tubes tandemly arranged, andconnected by rigid or revolute joints. One embodiment of the inventionis a composite steerable tube formed from two or more (e.g. 2, 3, 4, 5,6, 7, 8, 10 or more) motorised steerable tubes devoid of the proximalbendable zone 4 and proximal annular region 11 tandemly arranged, andconnected by rigid or revolute joints.

Using a more complex cutting pattern, strips 8, 8′ are within the scopeof the invention whereby one or more of the longitudinal strips 8, 8′are held together (interlocked) using interconnections (FIG. 8C),non-longitudinal slits (FIG. 8A), non-radial slits (FIG. 8B) orlongitudinal spiral cuts. In this constellation, the inner and outercoverings may be, but not necessarily, omitted. In this way, issues ofsterilization, concerning access of steam to all areas and tubes, can becircumvented. It is noted that another way to overcome problems withsterilization is to make the steerable tube and any covering or liningperforated and/or dismountable.

Where a non-radial slit is employed (FIG. 8B), the slit diverges fromthe radius of the elongate tubular member. FIG. 8B depict the profile ofslits taken in transverse (C-C′) cross-section across the bend-resistivezone. It is noted, the distance between respective strips isexaggerated; in practice the strips are in sliding contact. Normally,the slit 7, 7′ converges with the radius. When non-radial slits areused, the slits 7-1, 7-2 flanking a strip 8-1 may both diverge from theradius producing strips 8-1 with conical edges pointed outwards.Alternatively, when non-radial slits are used, the slits 7-3, 7-4flanking a strip 8-2 may both diverge from the radius producing strips8-2 with conical edges pointed inwards.

Annular Regions

Proximal to the proximal bendable zone 4 is a proximal annular region 11of the hollow elongate tubular member 1. The proximal annular region 11is adjacent and proximal to the proximal bendable zone 4. The proximalwires 9, 9′ may be anchored to the proximal annular region 11. Theproximal annular region may be circumferentially intact. In other wordsan intact region of the hollow elongate tubular member 1 may be uncut,having no slits or apertures, that would permit slidable movement withinthe proximal annular region 11. According to another aspect of theinvention, the proximal annular region 11 is composed of oneinterlocking part that folds cylindrically to form a region of fixedcircumferential shape. According to another aspect of the invention, theproximal annular region 11 is composed of two or more interlockingsubparts 46, 46′ (FIG. 14) that fits together cylindrically to form aregion of fixed circumferential shape. The interlocking arrangementprevents relative slidable movement between the subparts. By virtue ofthis property the distal annular region 12 may have a constant width;the width does not substantially change when the proximal bendable zone4 is flexed. The region may be ring-shaped. Wires 9, 9′ extending fromthe proximal bendable zone 4 are rigidly attached to the proximalannular region 11. Typically the wires 9, 9′ are evenly disposed aroundthe circumference of the proximal annular region 11.

Similarly, distal to the distal bendable zone 5 is a distal annularregion 12 of the hollow elongate tubular member 1. The distal annularregion 12 is adjacent and distal to the distal bendable zone 5. Thedistal wires 10, 10′ may be anchored to the distal annular region 12.The distal annular region may be circumferentially intact. In otherwords an intact region of the hollow elongate tubular member 1 may beuncut, having no slits or apertures that would permit slidable movementwithin the distal annular region 12.

According to one aspect of the invention, the distal annular region 12is composed of one interlocking part that folds cylindrically to form aregion of fixed circumferential shape. According to another aspect ofthe invention, the distal annular region 12 is composed of two or moreinterlocking subparts (FIG. 14) that fit together cylindrically to forma region of fixed circumferential shape. The interlocking arrangementprevents relative slidable movement between the subparts. By virtue ofthis property, the distal annular region 12 may have a constant width;the width does not substantially change when the distal bendable zone 5is flexed. The region may be ring-shaped. Wires 10, 10′ extending fromthe distal bendable zone 5 are rigidly attached to the distal annularregion 12. Typically the wires 10, 10′ are evenly disposed around thecircumference of the distal annular region 12.

The use of one or more interlocking parts to form the distal 12 andproximal 11 annular region allow an efficient construction of theelongate tubular member from one, two or more cut or molded parts (FIG.14) i.e. without the requirement for cutting an intact tube. Forexample, the elongate tubular member may be formed from a flat sheet ofmaterial, having the appropriate elements, folded cylindrically andjoined at the ends by virtue of interlocking circumferential joints inthe distal 12 and proximal 11 annular regions to form a working elongatetubular member. Alternatively, the separate strips, wires and annularregions segments, optionally thinned at the bendable zones, can beassembled by virtue of interlocking circumferential joints in the distal12 and proximal 11 annular regions.

The annular region 11, 12 can be of any longitudinal length depending onthe application. It should be of sufficient length, however, to provideenough strength that avoids distortion of the annular region 11, 12 bytensional forces in the wires 9, 9′, 10, 10′. Advantageously, it can beextended at the proximal end 2 in order to provide a greater leverage.Alternatively, it may be extended at the distal end 2 in order toprovide a greater movement. Shorter distal annular region 12 will allowfor a more precise angular control.

Materials of the Elongate Tubular Member

The elongate tubular member 1 can be made from any material whichprovides the requisite tensile and flexural properties. Suitablematerials include stainless steel, cobalt-chromium, shape memory alloysuch as Nitinol®, plastic, polymer, composites or other curablematerial. According to one aspect of the invention, the elongate tubularmember 1 is made from the same material throughout, e.g. stainless steelor nitinol. According to one aspect of the invention, the elongatetubular member 1 is made from two or more different materials, forinstance one material (e.g. stainless steel) in the bend-resistive zone6 and another material (e.g. nitinol) in the bendable zones 4, 5. Anexample of such configuration is given in FIGS. 16A and 16B anddescribed elsewhere herein. Alternatively different materials within thesame tube can be used e.g. extrusion with two different materials.

Shape and Dimensions of the Elongate Tubular Member

The elongate tubular member 1 preferably has a cylindrical shape in thenon-flexed stated, having a longitudinal axis A-A′ (FIG. 4A). Thedimensions discussed below refer to the elongate tubular member 1 in thenon-flexed state, and refer to a measurement at a maximum point and notto an average.

The total length of the elongate tubular member 1, L, from the tip ofthe proximal end 2 to the tip of the distal end 3 will depend on thematerials used in the elongate tubular member, considering itsstretching and pushability properties, thickness and diameter.Theoretically, any length of elongate tubular member is possibleproviding sufficient leverage is provide by the proximal bendable zone,for example, by extending the length of the proximal annular region. Inmedical applications, a total length of up to 150 cm would be desirable(e.g. endovascular catheters) for, and it is envisaged for mostapplications needing fine control (e.g. surgery and endoscopes) that thetotal length will be between 10 cm and 40 cm.

The length of the proximal bendable zone LP will depend on the materialsused in the elongate tubular member as mentioned above, and also thedegree of movement, force and accuracy needed. In general, the higherthe value of LP, the greater the force transmitted to the effector,though larger movements would be required. Values of LP are expect to be1%, 1.25, 2%, 2.5%, 3%, 3.5%, 4, 4.5%, 5%, 6%, 7%, 8%, 9%, 10%, 15% or20% the value of L. It is envisaged for most applications needing finecontrol that LP will be 0.5, 2 or 3 cm, preferably between 0.5 cm and 3cm for a 40 cm elongate tubular member 1.

The length of the distal bendable zone LD will depend on the materialsused in the elongate tubular member as mentioned above, and also thedegree of movement, force and accuracy needed. In general, the higherthe value of LD, the lower the force the end can apply, though thelarger the movements. Values of LD are expect to be 1%, 1.25, 2%, 2.5%,3%, 3.5%, 4, 4.5%, 5%, 6%, 7%, 8%, 9%, 10%, 15% or 20% the value of L.It is envisaged for most applications needing fine control that LD willbe 0.5, 2 or 3 cm, preferably between 0.5 cm and 3 cm for a 40 cmelongate tubular member 1.

The length of the proximal annular region LPR will depend on thematerials used in the elongate tubular member as mentioned above, andthe tensile (pulling) and compression (pushing) forces that the wiresapply so as not to distort the proximal annular region. In general, thehigher the value of LPR, the better the strength of the proximal annularregion. In addition, a higher value of LPR will provide more leverageand hence more force to the effect. Values of LPR are expect to be 0.25,0.5%, 0.625% 0.75%, 1%, 1.25, 2%, 2.5%, 3%, 3.5%, 4, 4.5%, 5%, 10% thevalue of L. It is envisaged for most applications where the proximalannular region will provide support and have no additional leverage thatLDR will be between 0.5 cm and 5 cm for a 40 cm elongate tubular member1.

The length of the distal annular region LDR will depend on the materialsused in the elongate tubular member as mentioned above, and the tensile(pulling) and compression (pushing) forces that the wires apply so asnot to distort the distal annular region. In general, the smaller thevalue of LDR, the better flexibility of the proximal annular region.Values of LDR are expect to be 0.25, 0.5%, 0.625% 0.75%, 1%, 1.25, 2%,2.5%, 3%, 3.5%, 4, 4.5%, 5%, 10% the value of L. It is envisaged formost applications where the distal annular region will provide supportLDR will be between 0.5 cm and 1 cm for a 40 cm elongate tubular member1.

The internal diameter of the bend-resistive zone IDS is at the option ofthe user, in accordance with the size of cables or other elements thatneed to pass through the lumen. For surgical applications, a value ofIDS between 1 mm to 8 mm, and 0.5 mm to 3 mm for endovascularapplication will cover most applications where fine control is necessarythrough a restrictive opening. Larger internal diameters are possible,for example, where mechanical structures are investigated and the sizeof the opening is not critical. The internal diameters of the proximaland distal bendable zones—IDP and IDD respectively—may be the same asthe IDS. As mentioned previously, the diameter of the proximal bendablezones may gradually increase towards the proximal end in order toincrease the bending couple i.e. leverage. According to one aspect ofthe invention, IDP may be 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 100%,200%, 300%, 400%, 500%, 600%, 700%, 800%, 900%, 1000%, 2000% or more,greater than IDS or IDD at its widest point, or a value in the rangebetween any two of the aforementioned values.

The external diameter of the bend-resistive zone ODS will be governed bythe size of the internal diameter, and the opening available. Forsurgical application, a value of ODS between 1 mm to 8 mm will covermost applications where fine control is necessary through a restrictiveopening. Larger external diameters are possible, for example, wheremechanical structures are investigated and the size of the opening isnot critical. The external diameters of the proximal and distal bendablezones—ODP and ODD respectively—may be the same as the ODS. As mentionedpreviously, the diameter of the proximal bendable zones may graduallyincrease towards the proximal end in order to improve flexibility.According to one aspect of the invention, ODP may be 5%, 10%, 15%, 20%,25%, 30%, 40%, 50%, 100%, 200%, 300%, 400%, 500%, 600%, 700%, 800%,900%, 1000%, 2000% greater than ODS or ODD at its widest point, or avalue in the range between any two of the aforementioned values.

The thickness of the wall of the elongate tubular member 1 is generallythe same throughout, i.e. values of TP (thickness of the wire in theproximal bendable zone), TS (thickness of the strip in thebend-resistive zone), and TD (thickness of the wire in the distalbendable zone), will be similar. The wall may have a substantiallyuniform thickness. For most applications, the inner diameter needs to bemaximized compared with the external diameter. However, in certainapplication, the walls may be thick relative to the inner diameter,leaving a small inner lumen, for example, just for a control cable. Thethickness of the wall may be 0.1 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, or 6mm, preferably between 0.1 to 0.6 mm, though the skilled person willappreciate it will vary according to the material properties. Asmentioned earlier, the wall can be thinned in either or both bendablezones, typically by 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%.

The dimensions mentioned herein are provided strictly for guidance. Theskilled person would appreciate that the dimensions of the elongatetubular member can be adapted within the teachings of the presentinvention and thus other dimensions are likewise feasible within thescope of the present invention.

Manufacture of the Tube

The transmission and bending properties of the elongate tubular membermay be provided by the pattern of cuts e.g. longitudinal cuts in thebend-resistive zone 6 (transmission). Additional flexibility may beprovided by cut-out apertures in the bendable zones 4, 5. A standardtechnique for the construction of a elongate tubular member of thepresent invention is laser cutting technology (FIG. 3A) which canproduce the instrument in an automatic manner e.g. by computer numericcontrolled (CNC) cutting. Adjustments to the cutting due to differentlengths or diameters of tubular member 1 can be automatically computedand modified cutting regimes implement. Other methods may also besuitable, including water jet cutting, electrochemical etching,electrical discharge machining, diamond cutting, simple knife cutting,or any other suitable technique preferably followed by a suitablesurface treatment, like etching or electro-polishing to deburr and orround off possible sharp edges.

As described elsewhere in the elongate tubular member may be formed froma flat sheet of material, appropriate cut, molded or stamped, that isbent cylindrically and joined at the mutual adjacent edges by virtue ofinterlocking circumferential joints in the distal 12 and proximal 11annular regions to form a working elongate tubular member.

It is within the scope of the invention that each strip 8 of theelongate tubular member 1 is formed individually. Formation might beachieved using any number of techniques, for example, by a molding orstamping process. Molding processes are well known in the art;typically, a polymer in the liquid state is injected into a moldcorresponding to the desired shape, in which the polymer hardens. Thehardened product may be subjected to a suitable surface treatment, suchas polishing to deburr and or round off possible sharp edges. Stampingtechniques are well understood in the art; typically a cutting stamp,having an outline shape corresponding to the desired product shape isapplied to a sheet of material such as polymer or metal. The product soformed may be curved by passing through rollers or by molding over acurved surface. The plurality of strips 8 so formed is used to assemblethe elongate tubular member 1. It will be appreciated that the abovetechniques may be applied to form segments of the elongate tubularmember 1. A segment comprises a strip 8, attached wires 9, 10 and asegment of the proximal 11 and distal 12 annular regions disposed withinterlocking cut-outs or interconnections (e.g. dove-tail joints or thelike) holding adjacent segments of the annular regions togethercircumferentially. In particular, the elongate tubular member 1 depictedin FIG. 14A may be formed in this manner.

Where the elongate tubular member 1 is formed from two or more differentmaterials, for example, the bend-resistive zone 6 made from stainlesssteel and the bendable zones 4, 5 made from nitinol, said materials maybe joined, for instance, by welding or gluing together intact tubesprior to cutting, and then cutting the compound tube so formed.

Alternatively, separate tubes formed from the different materials may becut according to the invention that are later joined using jointscreated by the cutting process as seen, for example, FIG. 16B.Alternatively, separate elements of the elongate tubular member (e.g.strips 8, wires 9, 10, proximal and distal annular regions 11, 12) maybe formed separately, and joined, for example, by welding, gluing orsoldering.

Outer Sheath

An outer sheath 20 (FIGS. 2A and B, FIG. 7) may be present in asteerable tube of the invention, which outer sheath 20 at least partlycovers the outside surface of the hollow elongate tubular member 1.Preferably, the outer sheath 20 covers at least the bend-resistive zones6 and the bendable zones 4, 5. The outer sheath 20 protects the hollowelongate tubular member 1 from dirt and obstruction while permittingtranslational movements of the strips 8, 8′ and wires 9, 9′, 10, 10′within. In this regard, the outer surfaces of the strips 8, 8′ and wires9, 9′, 10, 10′ may be coated with a lubricating substance, such a Teflonor silicone. In addition, the surfaces (e.g. outer and/or inner) of theouter sheath 20 may also be coated with a lubricating substance, such aTeflon or silicone. The outer sheath may play a constraining role toprevent the strips 8, 8′ and wires 9, 9′, 10, 10′ from bending outwards.Therefore, the outer sheath will have the necessary tensile properties,showing no or little elastic behaviour in order to constrain radialforces of the strips 8, 8′ and wires 9, 9′, 10, 10′. The outer sheath 20may be liquid or gas impermeable. The outer sheath 20 is preferablythin-walled, and constructed to exhibit flexibility in the bendablezones 4, 5. It is preferably cylindrical.

In a preferred aspect of the invention, and with reference to FIG. 7 theouter sheath 20 is made of a hollow tube 21 having a proximal end 22,distal end 23, a wall surface disposed between said proximal 22 anddistal end 23, the wall having a substantially uniform thickness, aflex-resistive region 26 flanked by proximal 24 and distal 25 flexibleregions, whereby the internal diameter of the hollow tube 21 is greaterthan the external diameter of the elongate tubular member 1. The hollowtube 21 is preferably placed over the tubular member 1 and co-axiallyaligned therewith so that the flex-resistive region 26 covers thebend-resistive zone 6, the proximal 24 and distal flexible regions coverthe proximal 4 and distal 5 bendable zones of the elongate tubularmember 1 respectively.

The wall of the hollow tube 21 in the flex-resistive region 26 isessentially intact, preferably being devoid of slits or apertures. Theflex-resistive region 26 is less flexible than the flexible regions 24of the outer sheath. The wall of the hollow tube 21 in the proximalflexible region 24 and the distal flexible region may comprise astructure that is a plurality of linkages 28 separated by strain-reliefapertures 29, which linkages 28 and apertures 29 allow the secondtubular member to flex. Two or more separate series of such apertures 29may be formed adjacent one another on opposite or different sides asshown in FIG. 7 of the tubular body to permit deflection or bending ofthe tubular body in multiple directions about its longitudinal axis(F-F′). Other known techniques that make rigid tubes more flexible arethe use of spiral cuts, hinges cuts, dove-tail cuts, and heart-likecuts. The apertures and patterns can be cut using the methods mentionedherein, in particular laser cutting technology. To better control thebending radius, for instance less bending in the distal portion of theproximal bending zone, the apertures (or linkages) may have differentsizes. The hollow tube 21 can be made from any biocompatible materialwhich provides the requisite elastic and flexural properties. Suitablematerials include stainless steel, cobalt-chromium, shape memory alloysuch as Nitinol®, plastic, polymer, composites or other curablematerial.

FIG. 7 depicts a perspective view of an instance of an outer sheath 20.Shown is the wall of the sheath 21 in the flex-resistive region 26devoid of apertures. The essentially continual wall structure reducesthe flexibility of the flex-resistive region 26.

It is within the scope of the invention, that the outer sheath 20 isformed from a tube that has inherent flexible properties, for examplebeing made from material such as PTFE, polypropylene, or other siliconeor rubberised polymeric substances which exhibits flexibility in theproximal bendable zone 4 and the distal bendable zone 5 when the outersheath co-axially covers the elongate tubular member 1. The regioncovering the bend resistive zone 6 may be reinforced with to resistradial expansion or increase torsional stiffness, for example, usingbraiding. To prevent penetration of substances through the strain-reliefapertures. an additional liquid impermeable cover (PTFE, silicone, heatshrink wrapper) may be utilised.

According to one aspect of the invention, the outer sheath 20incorporates a braking mechanism, configured, when activated to preventslidable movements by the strips 8, 8′ of the elongate tubular member 1.When the brake is applied, the position of the distal bendable zone 5 isfixed; i.e. it becomes resistive to force applied thereto. The brake maytake any form, for example, a compressible annular ring having an innerdiameter that varies according to the degree of compression. The innercircumference of the ring applies pressure to the strips 8, 8′ of theelongate tubular member 1 when the ring is compressed along its centralaxis.

As already mentioned above, the outer sheath can be omitted by observinga more complex cutting pattern; the strips 8, 8′ are envisaged which areheld together (interlocked) using interconnections (FIG. 8C),non-longitudinal slits (FIG. 8A), non-radial slits (FIG. 8B) orlongitudinal spiral cuts. In this constellation, the inner and outercoverings may be, but not necessarily, omitted. In this way, issues ofsterilization, concerning access of steam or plasma to all areas andtubes, can be circumvented.

Inner Lining

An inner lining 50 (FIGS. 2A and B) may be present that at least partlylines the lumen 15 of the hollow elongate tubular member 1. The innerlining 50 protects the inside hollow elongate tubular member 1 from dirtand obstruction while permitting translational movements of the strips8, 8′ and wires 9, 9′, 10, 10′ outside. In this regard, the innersurfaces of the strips 8, 8′ and wires 9, 9′, 10, 10′ may be coated witha lubricating substance, such a Teflon or silicone. In addition, thesurfaces (e.g. outer and/or inner) of the inner lining 50 may also becoated with a lubricating substance, such a Teflon or silicone. Theinner lining may play a constraining role to prevent the strips 8, 8′and wires 9, 9′, 10, 10′ from bending inwards. Therefore, the innerlining will have the necessary compression properties, showing no orlittle elastic behaviour in order to constrain radial forces of thestrips 8, 8′ and wires 9, 9′, 10, 10′. The inner lining 50 may be liquidor gas impermeable. The inner lining 50 is preferably thin-walled, andconstructed to exhibit flexibility in the bendable zones 4, 5. It ispreferably cylindrical.

Preferably, the inner lining 50 is formed from a tube that has inherentflexible properties, employing a material such as PTFE, polypropylene,or other silicone or rubberised polymeric substances. The inner lining50 may be formed from an inherently inflexible tube, made flexible bythe addition of apertures cut from the tube walls and as describedelsewhere herein. Preferably, the hollow tube is flexible over its wholelength.

The use of an inner lining 50 is not essential. The lumen 15 of thehollow elongate tubular member 1 can be obturated for example with alaser fiber, control cable for grasping forceps or scissors, aspirationcatheter, bundle of glass fibers, power or data cables, a flexible rodwith a lumen for electrical wires.

According to one aspect of the invention, the inner lining 50 is made ofa hollow tube having a proximal end, distal end, a wall surface disposedbetween said proximal and distal end, the wall having a substantiallyuniform thickness, a flex-resisitive zone flanked by proximal and distalflexible region, whereby the external diameter of the hollow tube isless than the internal diameter of the tubular member 1. The hollow tubeis preferably placed within the tubular member 1 and co-axially alignedtherewith so that the flex-resisitive region covers the bend-resistivezone, the proximal and distal bendable zones cover the proximal 4 anddistal 5 and flexible regions respectively. FIG. 2B depicts an innerlining 50 within the proximal bendable zone 4, having walls containingapertures and linkages, similar to the hollow tube 21 that forms theouter sheath 20. The embodiments above and which describe FIG. 5 of theouter sheath 20 may be readily adapted to prepare an inner lining withthe above mentioned properties.

Additionally coaxial steering tubes can allow indifferent flexion ondifferent parts of the complete tube FIG. 13A. This could allow surgeonsto go through one incision with two or more instruments. After enteringthe abdomen a first joint brings the instrument lateral while a secondallows coming back medially towards the operative field. This conceptallows performing the operation through one incision while maintainingan on-obstructed view on the operative field.

Adaptations

As mentioned earlier, the proximal or distal ends of the instrument maybe adapted with particular tools or components which may be attached tothe tubular member, and/or to the optional outer sheath and/or to theoptional inner lining. According to one example, the proximal end 2 maybe adapted with a handgripper 70 which controls a set of forceps 80 atthe distal end 3, which forceps 80 are controlled by a control cable 75passing through the lumen, connected to the handgripper 70 (FIGS. 15A to15D). The handgripper 70 may be formed from an essentially solid-walledthin tube, cut according to the techniques described herein. Suchhandgripper is shown in FIGS. 15A and 15B. The two handles 71, 72 of thegripper 70 are formed by a pair of longitudinal cuts, and one hingehandle 72 is created by a circumferential cut which creates two revolutejoints 76 at the corners of the one hinge handle 72. Supporting struts73 for the control cable 75 may be cut from the handles 71, 72.Alternatively, instead of supporting struts an additional laser cutring-like structure that becomes oval when compressing the handles maybe employed. In this way, hinged movement by the handle 72 is convertedto a linear movement by the wire 75.

Similarly, the forceps 80 may be formed from an essentially solid-walledthin tube, cut according to the techniques describe herein. Such forceps80 is shown in FIGS. 15C and 15D. The two jaws 81, 82 of the forceps 80are formed by a pair of longitudinal cuts, and one hinge handle 72 iscreated by a circumferential cut which creates two revolute joints 76 atthe corners of the one hinge handle 72. A supporting strut 83 for thecontrol cable 75 may be cut from the two jaws 81, 82. In this way, alinear movement by the control cable 75 is converted to a hingedmovement by the jaw 82.

According to one embodiment of the invention, the strips 8, 8′ of thehollow elongate tubular member 1 are made from one material, while thewires 9, 9′ are made from another material. The wires and strips 8, 8′are joined by interconnecting joints (FIG. 16A). Such hybrid structuremight be of use to reduce the costs when expensive material are employedsuch as Nitinol; in such case, Nitinol may be used to form the wires 9,9′ and annular regions 11, 12, while a cheaper alloys used to form thestrips 8. Alternatively the wire could be replaced by small Nitinol rodsinserted in the annular region and strips (FIG. 16B).

For difficult-to-see and/or hard-to-reach places, the distal end 3 mayadvantageously by provided with an endoscopic camera or lens, which maybe implemented by fiber scope or chip-on-a-stick.

According to one aspect of the invention, the steerable tube 100 furthercomprises a cutting tool at the distal end 3. The cutting tool can beany, including but not limited to scissors, knife, drill, mill, grinder,saw, or knibbler.

According to another aspect of the invention, the steerable tube 100further comprises a sensor at the distal end 3. The sensor is preferablyelectronic, and concerts the detected phenomenon into electricalsignals. The sensor can be any, including, but not limited totemperature, moisture, light (wavelength and/or intensity), gas,radioactivity, acoustic, and pressure.

According to one aspect of the invention, the steerable tube 100 furthercomprising one or more electrodes at the distal end 3. The electrode canbe any, including, but not limited to stimulation, recording,coagulation, reference.

Another embodiment of the invention is an endoscope disposed with aplurality of lumens, whereby at least one lumen (for example, 1, 2, 3 ormore) is provided with a steerable tube of the present invention. It isnoted that the narrow profile of the steerable tubes allows theconstruction of an endoscope of standard diameter (e.g. 6.2 mm)comprising two steerable tubes, one in each lumen. Exceptionally, thepresence of two steerable tubes permits co-operation at the tip,exemplified with one tube being disposed with a remote-controlled jaw tograsp an object and another tube disposed with a remote-controlledcutter, to sever the object. This level of control and co-operationbetween instruments has never before been achieved through narrow tubeendoscopes.

Further, the wide internal diameter of the steerable tube facilitatesits role in aspiration such that excised tissue can be removed throughthe steerable tube without blockage. It is envisaged that, particularlyin bodily-invasive procedures, the invention permits safer and morerapid manipulations while reducing the risk of infections.

Steering Guide

Another embodiment of the invention is a steering guide 119, exemplifiedin FIG. 17, configured for attachment to a part of the bodily arm of theuser and which supports, through an attached endoport device 160(described further below), an invasive medical instrument 120 disposedwith a longitudinal axis, including, but not necessarily limited to thesteerable tube 100 of the present invention, permitting pivotal movementof the instrument 120, said pivotal movement actuated by said part ofthe arm. The pivotal movement referred to herein is the movement withina conical space around the point of a cone centered on a fulcrum point.Thus, the pivotal movement of the endoport device 160 attached to thesteering guide is around a fulcrum point 136. The fulcrum point 136 ofthe endoport device 160 coincides with a point along the device bodywhere it rests in the incision. The steering device positions theproximal end of the instrument 120 within reach of the user's hand 138which can access and operate controls thereon, independent of adjustingthe pivotal position of the instrument, which is performed by the arm.The user's wrist joint effectively isolates movements by the hand 138from movements of the arm part. The steering guide 119 takes advantageof the isolated movement to operate any proximally-situated controls ofthe medical instrument simultaneous with adjusting its position in theavailable working space.

The steering guide 119 may comprise an elongated longitudinal member 122having a proximal 126 and distal 128 end, the proximal end 126 disposedwith a brace 123 for attachment to a part of a bodily arm, and thedistal end 128 disposed with an endoport device 160, configured forattachment to the medical instrument 120.

The elongate longitudinal member 122 is essentially rigid, and at leastspans the length between the brace 123 and a point distal to (beyond)the hand 138 of the user. It is preferably made from a light weightmaterial such as aluminum, titanium, polymer (e.g. polycarbonate), orcomposite. It may be formed from a solid rod, hollowed rod, or from arod with transverse openings. The material used to form the elongatelongitudinal member 122 may not inherently possess the requisiterigidity in the rod form, in which case the structure may bestrengthened with one or more cross supports. The elongate longitudinalmember 122 may be straight at least in part. The distal end 126 may beshaped (e.g. curved) to create a volume that accommodates a range ofmovement by the hand 138. The distal end 126 may be further shaped (e.g.curved) to bring the endoport device 160, in particular the passagetherethrough, in co-axial alignment with the longitudinal axis of thelower arm 128.

The brace 123 attaches the elongated longitudinal member 122 to a partof the bodily arm of the user. The brace 123 may be adapted forattachment to any part of the arm, for instance, the upper arm 130,lower arm 131 or elbow 132. The brace 123 may be attached to theproximal end 126 of the elongated longitudinal member 122 using afixture 134 that allows slidable movement of the elongated longitudinalmember 122 relative to the brace 123. The fixture 134 may further beconfigured to limit or allow pivotal movement of the elongatedlongitudinal member 122 relative to the brace 123. The fixture 134exemplified in FIG. 17 comprises a protruding rigid eyelet through whichthe elongate longitudinal member 122 passes, and can pivot and sliderelative to the eyelet. The brace 123 may be configured to orientate thelongitudinal member 122 essentially parallel to the lower arm 131. Thebrace 123 may be configured to position the endoport device 160 at apoint distal to (beyond) the hand 138 of the user. Movements of the arm,e.g. the upper arm 130, lower arm 128 or elbow 132 are directlytransmitted along the elongated longitudinal member 122 to the endoportdevice 160 which they are realised as pivotal movements.

The brace 123 may be formed from a cylindrical ring, with a centralpassage in which the arm part lies. It is preferably formed from aninelastic cloth cuff configured to wrap around the arm part, anddisposed with a securing means such as one or more Velcro® strips.

The endoport device 160 is attached to the distal end 128 of theelongated longitudinal member 122. The endoport device 160 is configuredto couple with the longitudinal axis of the medical instrument 120. Theendoport device 160 may permit slidable and rotational movement of themedical instrument relative thereto, which movements are lockable.Typically the endoport device 160 comprises a cylindrical passage inwhich the instrument 120 rests, and optionally a locking mechanism thatholds the instrument 120 in fixed position with respect to the endoportdevice 160. The locking mechanism may comprise a nut or pin, thatfrictionally contacts and applies locking pressure to the body of theinstrument. The central axis of the cylindrical passage of the endoportdevice 160 is preferably substantially co-axially aligned with thelongitudinal axis of the lower arm. The endoport device 160 may attachto the elongated longitudinal member 122 with an adjustable jointconfigured to lockably adjust the orientation of the central axis of thecylindrical passage relative to the longitudinal axis of the lower arm.The joint may permit rotational movement by the endoport device 160 intwo or three dimensions.

The elongated longitudinal member 122 may be rigidly attached to an openkinematic chain comprising a plurality (e.g. 2, 3, 4, 5, 6 or more) oftandemly arranged, rigid links, connected by lockable joints (e.g.revolute and/or ball and socket), which kinematic chain permits movementof the elongated longitudinal member 122 when the joints are not locked,and which prevents movement by the elongated longitudinal member 122when the joints are locked. The open kinematic chain typically has abase link, rigidly attached at one end to the operating table, and aneffector link attached to the elongated longitudinal member 122. One ormore links may be disposed between the base and effector links. It willbe understood that, in accordance with kinematic principles, the morejoints employed, the more degrees of freedom of movement permitted bythe longitudinal member 122 attached to the effector link. Typically thetotal number of joints is 3, 4, 5, 6 or 7 or more. A 6 joint openkinematic chain provides 6 degrees of freedom in its workspace. Thelocking mechanism of the revolute joints can be any, including amechanical, electromagnetic, pneumatic or hydraulic brake, preferablyactuated by a foot pedal or lever.

The steering guide is suitable for use with any medical instrument thatwould benefit from setting its pivotal orientation, such as thesteerable tube of the invention, any steerable tube, or a laparoscope.In general the medical instrument has a longitudinal axis, and a bodythat is capable of being held by the endoport device 160.

The pivotal movements of the medical instrument 120 are actuated by apart of the human arm, for instance, the upper arm 130, lower arm 131 orelbow 132, leaving the hand free to operate the instrument, forinstance, levers, buttons, controllers, disposed at the instrument'sproximal end. When the instrument is a steerable tube 100 of the presentinvention, the hand is able to operate the controller at the proximalend so changing the position of the tube distal end, in addition tooperating any handles e.g. for a distal cutter or gripper, withoutdisturbing the pivotal position of the instrument which is controlled bya separate part of the body i.e. the arm, optionally locked by alockable kinematic chain.

Lockable Articulated Arm

Another embodiment of the invention is a lockable articulated armcomprising a plurality (e.g. 2, 3, 4, 5, 6 or more) of tandemlyarranged, rigid links connected by lockable joints, having at one end abase link configured for rigid attachment to an operating table, and atthe other end, an effector link connected to a lockable ball and socketjoint, the ball and socket joint configured for coupling to an endoportdevice, through which a medical instrument disposed with a longitudinalaxis, including, but not necessarily limited to, the steerable tube ofthe present invention is disposed, which lockable ball joint is furtherconfigured to pivot the endoport device relative to the effector link.The lockable articulated arm allows the user to orient the effector linkwithin a working volume and to set the desired position. Having set thedesired position in three-dimensional space, the medical instrumentdisposed on the effector link may be independently pivoted around theball and socket joint, and the desired pivotal position also locked.

According to one aspect of the invention, the lockable articulated arm,as shown in FIG. 18, comprising a plurality of tandemly arranged, rigidlinks 172, 174, 176, 178 connected by lockable joints 180, 182, 184,which arm 170 permits movement of the links 172, 174, 176, 178 when thejoints 180, 182, 184 are not locked, and which prevent movement by thelinks 172, 174, 176, 178 when the joints 180, 182, 184 are locked. Thearticulated arm 170 typically has a base link 172, rigidly attached atone end to the operating table 171, and an effector link 178 connectedat one end to a ball and socket joint 152 to which an endoport device160 attaches, and through which an invasive medical instrument 120disposed with a longitudinal axis, including, but not necessarilylimited to the steerable tube 100 of the present invention is disposed.One or more links 174, 176, may be disposed between the base 172 andeffector 178 links. It will be understood that the more joints employedin the arm, the greater the degree of freedom of movement i.e. workingspace permitted by the terminal end of the effector link 178, and thusby the medical instrument 120 attached thereto. Typically the totalnumber of joints is 3, 4, 5, 6 or 7 or more.

One pair of links is preferably connected by one joint. It will also beappreciated that the type of joints 180, 182, 184 employed between thelinks 172, 174, 176, 178, whether they be revolute, ball and socket, ora mixture, also influences the volume of the working space of theterminal end of the effector link 178. In FIG. 18, the first jointbetween the base link 172 and the first link 174 is revolute; the secondjoint 182 between the first link 174 and second link 176 is a ball andsocket joint; the third joint 184 between the second link 176 and thirdlink 178 is revolute.

The locking mechanism of the joints 180, 182, 184 can be any, includinga manual mechanical mechanism actuated by a lever 185 as shown in FIG.18, or electromagnetic, pneumatic or hydraulic brake, preferablyactuated by a foot pedal. Preferably the joints lock simultaneously.

The ball-joint port 152 is also lockable (FIG. 19), meaning that thepivotal position of the endoport device 160 can be set and locked at aposition within the range of possible movement of the ball joint. Thelocking mechanism can be any, including, for example, a pin, screw, orcollar that frictionally contacts the ball 154 when advanced theretowards, or a contractable socket 156.

As described earlier, the effector link 178 is attached to one part of aball and socket joint (e.g. the socket), while the other part of thejoint (e.g. the ball) attaches to the endoport device. According to theembodiment depicted in FIG. 19, the ball 154, having a spherical shape,is provided with a diametric bore 158 passing completely through theball, adapted to support the endoport device 160. The bore 158 may beconfigured to permit no or limited slidable or axial-rotational movementby the endoport device 160 relative to the ball 154. The ball 154 mayincorporate a locking mechanism allowing slidable movement by theendoport device 160 in an unlocked mode, and substantially no slidableor axial-rotational movement by the instrument relative to the ball 152in a locked mode.

The endoport device 160 used in both the steering guide 119 and lockablearticulated arm 170 is known in the surgical field. For guidance, abrief description follows. The endoport device 160 comprises a hollowtubular member 162 configured for insertion through an incision in asubject (e.g. a patient), open at one end, and is attached at the otherend to a head section 166 comprising a fitting 164 for a source ofpressurised gas such as carbon dioxide. The fitting 164 may be a Luerfitting, preferably provided with a screw thread. Gas passing throughthe fitting 164 is directed to the hollow tubular member 162, therebypermitting inflation of the cavity being surgically accessed when thedevice is in situ. The hollow tubular member 162 may be disposed withone or more side ports (not shown) for gaseous outlet. The head section163 further comprises a linear passage in coaxial alignment with thecentral axis of the hollow tubular member 162 which passage is also influidic connection with the hollow of the tubular member 162. Thecombined cylindrical passage so formed, spanning the head and tubularmember is suitable for receiving an invasive medical instrument 120disposed with a longitudinal axis, including, but not necessarilylimited to the steerable tube 100 of the present invention. When used inconjunction with the lockable articulated arm 170 of the invention, partof the hollow tubular member 162 of the endoport device 160 attaches tothe ball and socket 152. As shown in FIGS. 18 and 19, the hollow tubularmember 162 passes trough the bore 158 of the ball 153, and contacts thehead 166.

The lockable articulated arm 170 is suitable for use with any medicalinstrument that would benefit from setting a spatial and pivotalorientation, such as the steerable tube of the invention, any steerabletube, or a laparoscope. In general the medical instrument has alongitudinal axis and a body that capable of being held within the bore158 of the ball 154.

The particular combination of parts described and illustrated herein isintended to represent only one embodiment of the invention, and is notintended to serve as limitations against alternative devices within thespirit and scope of the invention.

What is claimed is:
 1. A steerable tube, comprising a steering mechanismformed as a hollow elongate tubular member, one end being a controllercomprising a proximal bendable part, the other end being an effectorcomprising a distal bendable part, wherein movements of the controllerare transmitted via the hollow elongate tubular member to the effectorwhich moves responsive to movements of the controller, the steeringmechanism configured for omnidirectional control and movement of theeffector and for axial rotation of the effector in the bent position. 2.The steerable tube according to claim 1, wherein the tubular membercomprises a plurality of longitudinal members connecting the controllerto the effector.
 3. The steerable tube according to claim 2, wherein thelongitudinal members are formed by cutting the tubular member or bycutting a flat sheet that is subsequently bent to form the tubularmember.
 4. The steerable tube according to claim 2, wherein thelongitudinal members are formed individually.
 5. The steerable tubeaccording to claim 2, wherein the longitudinal members are disposed inalignment with or inclined to a longitudinal axis of the hollow elongatetubular member.
 6. The steerable tube according to claim 2, wherein thelongitudinal members are provided as spiral strips.
 7. The steerabletube according to claim 1, wherein a diameter of part of the tubularmember progressively increases towards a proximal end of the steerabletube to increase leverage of the controller.
 8. A multi jointedsteerable tube having a proximal end and a distal end, comprising atleast two steering mechanisms, a first steering mechanism formed from afirst hollow elongate tubular member one end being a first controllercomprising a first proximal bendable part, the other end being a firsteffector comprising a first distal bendable part wherein movements ofthe first controller are transmitted via the hollow elongate tubularmember to the first effector which moves responsive to movements of thefirst controller, the first steering mechanism configured foromnidirectional control and movement of the first effector, a secondsteering mechanism formed from a second hollow elongate tubular memberone end being a second controller comprising a second proximal bendablepart, the other end being a second effector comprising a second proximalbendable part, wherein movements of the second controller aretransmitted via the hollow elongate tubular member to the secondeffector which moves responsive to movements of the second controller,the second steering mechanism configured for directional control andmovement of the second effector, wherein the two tubular members aremutually co-axially arranged, and the first steering mechanism isconfigured for axial rotation of the first effector in the bentposition, and/or the second steering mechanism is configured for axialrotation of the second effector in the bent position, and the secondcontroller is provided distal of the first controller and the secondeffector provided proximal of the first effector, or the secondcontroller is provided proximal of the first controller and the secondeffector provided proximal of the first effector and distal of the firstcontroller.
 9. The multi jointed steerable tube according to claim 8,wherein the first tubular member comprise a plurality of firstlongitudinal members connecting the first controller to the firsteffector, and the second tubular member comprise a plurality of secondlongitudinal members connecting the second controller to the secondeffector.
 10. The multi jointed steerable tube according to claim 9,wherein the first longitudinal members are formed by cutting the firsttubular member or by cutting a flat sheet that is subsequently bent toform the first tubular member, and second longitudinal members areformed by cutting the second tubular member or by cutting a flat sheetthat is subsequently bent to form the second tubular member.
 11. Themulti jointed steerable tube according to claim 9, wherein the firstlongitudinal members are formed individually, and the secondlongitudinal members are formed individually.
 12. The multi jointedsteerable tube according to claim 9, wherein the first and/or secondlongitudinal members are disposed in alignment with or inclined to alongitudinal axis of the hollow elongate tubular member.
 13. The multijointed steerable tube according to claim 9, wherein the first and/orsecond longitudinal members are provided as spiral strips.
 14. The multijointed steerable tube according to claim 8, wherein the second steeringmechanism is configured for omnidirectional control of the secondeffector.
 15. The multi jointed steerable tube according to claim 8,wherein a diameter of part of the first tubular member progressivelyincreases towards the proximal end to increase leverage of the firstcontroller.
 16. The multi jointed steerable tube according to claim 8,wherein a diameter of part of the second tubular member progressivelyincreases towards the proximal end to increase leverage of the secondcontroller.
 17. The steerable tube according to claim 1, wherein themovements of the controller are servomechanically actuatable.
 18. Themulti jointed steerable tube according to claim 8, wherein the movementsof the first and second controller are each servomechanicallyactuatable.